Steam-engine cycle



F. J. WOOD. STEAM ENGINE CYCLE. APPLICATION FILED DEC-27. 1917- RENEWED DEC- 21, I920. 1,434,079.

Patented 0c Inventor.

wLtnEssEs:

Patented Get. 31, 1922.

units FRANK JJWOOD, OF-BROOKLYN, NEW 'YORK.

STEAM-ENGINE CYCLE.

Application filed December 1917, Serial N0.'209,120j.

ToaZZ whom it may concern:

Be it known that I, FRANK J. ll' oomacitizen of the llnited States, residing at No. 153 Joral'emon tit, Brooklyn Borough, city of New Yorln-and' State of ll ew Tor-L1,: have in rented new and useful liiiproveinents in a Steaui-Phnrine C-ych-r, ot-which the 'Follow in o; is a specification The object of my invention is to provide a method oi usingsteam in the generation of power, that will convert into mechanical energy more of the heatthat is contained in steam thauis practicable in the ordinary steam engine cycle and by the. method o't working herein described I can utilize much 01? the latentheat thatordinarily escapes through the exhaust pipe. The action of the ordinary tornr of steam engine .in which steam is introduced into each end ota cylinder at thecommencement of the stroke of the piston, and is cut off later on in the stroke and thenexerts more or less of a pressure to the end ot the stroke is too well known to describe fully in detail, so when I refer to certain actions that take place in ordinztr) forms of steam engines I consider that it is unnecessaryto explain fully every movement of the parts of the whole engine.

lt is well known that during the stroke of the piston of an ordinarysteaur engine, utter cutting of? takes place the steam expands and throughout the ren'iainder oi the stroke the pressure and temperature generally i: 'duces. It is alsowell known that it compressed air at thesame pressure could,

with the same cut oil be used to-actuate the same steam engine, after cutting off the pressure and temperature would reduce more in proportionthan When steani is used. For instance, if thecutting oil? takes place when the steam pressure is lbs. and 2S0 dean-es temperature, and I the piston advances until. the steam expands to atmospheric oressure, then the temperature will be degrees; while if air is used and at the point of cut off the pressure is 85 lbs, and the temperature has been. raised to 280 degrees, then it thepiston advances until the pressure I'Otillltfitl to atmospheric, the temperature of the expandedairwill be about (30 degrees.

It is well known that saturated steamdurinn; expansion after cutting off will partially condense into fine particles of water which for a short. time remain suspended in the gaseous steam in the form of a mist. It

this steam with its suspended particles of watercould be exhausted from the cylinder into a large tank and be brought to a coinparatively motionless state therein, these particlesoi water will. settle to the bottom. as there always an evolution of heat when steam changes to water, mostly for this reason the temperature oi? steam is higher at the end of the stroke than air is when GX- paneled from. the same initial pressure. The steanr that condenses and enters into the for mation of these particles of water gives up its'lat'ent heat to the enveloping gas as the particles of water are formed during; expansion;

llow air alone in expanding in a steam enginecylinder does not partially condense into liquid particles in the same way that steam does, consequently, there being no stored up latent heat to draw upon the air must cool. to a lower ten'iperature. This cooling effect that air has during expansion, would, iira u'iixture of air and steam expanding iir air engine cylinder, cause a target proportion of the steamto condense. than if steanrwere used alone; and it ohi'ious that the lar er the proportion of air the greater the .oportion of steam that will be condensed.

The condensing ofthe steam in the mix ture being brought aboutto a large'extent hythe tendency olithe'air to reduce in tomperature while expamling, it is obvious that tlie air mustreceivc some of the latent heat given upby this condensing steam. It 'lfol lows then that nearly all or the steam in the steam and air mixture can be condensed it the proper proportions oi. steam and air are mixed at a certain temperature and then expanded a'suiticient number oi? volumes to bringthe mixture to a temperature that is considerably below the boiling point o't-water under the pressure to which the expansion is brought; Now if the air in this mixture re ceii'es this latent heat it must necessarily be expanded in Volume or raised in pressure overand above the volume or pressure that would prevail if airwcre used alone.

Raising the ten'iperature with this latent heat meansthat more Work can be put out by the piston from the samesteam and such being the case it is obvious that'an engine working a mixture made up of the right proportion of air and steam would be capable cl. converting'a Yery large proportion of the latent he: t oi the steam into work.

Renewed December 21, 1920. Serial No. 432,370.

valve.

To avoid a possible waste of latent heat it is practically necessary to exhaust in a closed chamber and draw from this chamber the same air over and over again for mixing with the steam. The conditions in the chamber can be arranged so that the air can be at all times a near approach to per cent humidity, while the air or the outside atmosphere varies "eatly. If air much below 100 per cent humidity be drawn into the cylinder and mixed with steam, much latent heat would get away in the exhaust in the form of uncondensed vapor mixed with the air, as the exhaust air can never be below the mum humidity. The latent heat value or the uucondensed vapor in the air is too much to be wasted when it is considcred that under normal conditions the volume of air that is used in the cylinder is many times thatol the steam. To get good ellic-iency the working cycle would be one that contemplates takinga certain volume o l air at practically 100 per cent humidity, compressing the same to a certain pres ure and t'c erature, then mixing a smaller volume 01 steam at about the same temperature and pressure, then during a working stroke expanding the mixture to a press re and temperature that will convert the st am to water more or less suspended in air, then separating the particles of water from the air, but leaving the air at about 100 per cent humidity, then using this air again as above described.

I am enabled to obtain these results by means of the engine described below and illustrated by the accompanying drawings in whirl 1, shows the engine and all at the llli'rl features more or less diagramniatically. Fig. 2, shows the pressure curves indicating approximately the pressure changes that occur during the stroke of the piston. Pressures and ten'iperatures are in dictated l; distances from the base line 50, 50. and distances alone; or parallel with the base line indicate stroke of piston. Points along the curves indicate pressures and temperatures at certain points in the stroke. In Fig. 1, the cylinder, 1. is mounted on a frame of the type that is not unusual in vertical engines. An elongated piston, having a lengtl nearly equal to the stroke i coni'iected by a piston rod, 3, to the usual. cross-head. connecting rod, crank shaft and fly-wheel. A suitable governor, 4, of any well known type which can control the stroke and cut oil of the slide valves, 4: and by shiftimg the throw of the eccentric 6. can be used. The exhaust port, 7, is so placed that the piston acts as the exhaust- This exhaust port communicates with the settling chamber, 8, through the pipe. 8. There are two valves, 9 and 10, which open inwardly'into the cylinder and which permits or" allow of air from the acall Olf the ai 1 ,aeenrs cumulating reservoir, 17, through the pipes, 11 and 12, into the ends of the cylinder, 1. The valves are prevented from being closed until the proper time by the valve motion, 13, l l, 15, and the eccentric 1.". The settling chamber, 8, is of such capacity that it will receive the exhaust flow from the engine and slowly carry it to the outlet, 18, with such a very slight amount of current that any liquid particles that may be suspended in the air in rture will tend to set tle. The deflecting balile, 19, and the porous screen, 2%, tend to project the liquid pars downwardly and then collect them 1' they issue -from the exhaust pipe, 8. pump, :21, draws the accumulation of water from the settling chamber, 8, and is used also to maintain a certain vacuum in this chamber. This pump, 21, is 01 such ca pacity that will pump all of the water of condensation and just sufiicient air to equal the leakage and that which is brought in mixed witl le s eam and bring about t 1 certain desired vacuum. A pump, 22, is arranged so that it will draw practically i ion of the mixture that issues from the Xhaust pipe, 8, into the l .r, and slightly compress it into the ace initiating: reservoir, 1'7. The two pipes id '12 communication between the initiating reservoir, 1.7 and the two check valves, 9 and 10. is occasionally an almormal influx of steam may occur, and it IS necessary to keep the chamber, 8. at a constant and. a comparatively low temperal insulate the shell of this chamber able thickness of any well known insulating material and to maintain at a comparatively low depro-71c the coolingcoil, 23, through rich flows coll solution that is cooled by means that will. produce acertain sufiici itlv low temperature. A pump, 2st, discharge" any water that might accumulate in reservoir, 17.

There are comparatively lar e clearance spaces, 30, 31. at the ends ()1 r. 1e cylinder. 1, in order that there will be room tor the air that is compressed to a. moderate pressure during the compression stroke or' the piston. The steam ports, 39', 33, are somewhat contracted. atthe openings into clearance spaces 30, 81, in order that the steam will flow into the clearance spaces with some velocity and have a jet action that will thorou 'hly mix the inflowin'gr steam with the co essezl air. The steam that flows through the ports. 32, 33, comes from the receives steam from steam supply through llil) 1 sa-me B 8, or the slight pressure in reservoir, 17,1301 it is obvious that with the steam valves and pumping attachments shown that pressure could be applied to the piston, a partial vacuum could be pumped in the chamber, 8, and a slight pressure over that of this partial vacuum could be pumped into the reservoir, 17, so that it is obvious that the engine could be started and be brought up to a suitable speed. Assuming that the engine is running at normal speed and at the instant that the piston is at the lower extreme of its stroke, air at lbs. pressure and 280 degrees temperature has been compressed by the piston, 1., into clearance space, 31. The valve, 5, over the port, 33, now opens and as the steam in the steam chest at a pressure slightly above 35 lbs. it blows into the cylinder through the contracted opening of the port 33, with such a velocity that the inflowing steam mixes intimately with the compressed air. The piston now moves upward and the steam valve over the port remains open until the cutting off point in the stroke of the piston reached. While the steam flows into the cylinder up to the cutting off point, the pressure in the cylinder is maintained approximately at 35 lbs. Aft-er cutting ofl expansion takes place and the pressure and temperature gradually lowers, the lowering temperature condenses more and more of the steam into a mist until the end of the stroke is reached then the piston uncovers the exhaust port, 7, and the air, mist and remaining steam is free to flow through the pipe 8. As there has been pumped a slight pressure in reservoir, 17, over that in the chamber, 8, this pressure is sufficient to open the check valve, 10, and the air that now flows freely into the cylinder. flushes air, mistand steam out through the exhaust port, 7, into the se tling chamber, 8. The displacing humid air that fills the cylinder when the exhaust port is again covered by the piston on the return stroke is for a short time prevented from compressing by the valve, 10, being held open by the valve motion and eccentric, 13, 14-. 15 and 16. This valve motion is so timed in its action that the valve, 10, is seated when the piston arrives at the certain point in its stroke that the compression at the end will be approximately lbs. The temperature should be approximately 280 degrees when the compression is completed. and this temperature is obtained more by compressing but depends to a certain extent on the temperature of the air at the moment com pressing commences; this commencing oi compression temperature is more or less controlled by maintaining a certain temperature in the chamber, 8, by means of the cooling coil. 23. At the moment that the mixture of air, mist and possibly steam issues from the exhaust pipe 8. into the chamber 5 the mixture is deflected downward by the bafiie, 19, and then through the perforated or porous screen, 24, in order that the particles of water may be brought towards the bottom and together. The volume of this settling chamber being greatly larger than the volume of the cylinder of the engine, there isnot su'lfioient current to carry the particles of water up with the air so the air is drawn .into the pump, 22, in a state that is of maximum humidity but con'iparatively free of mist and is slightly compressed as it is stored in the reservoir, 17.

The engine as shown being double acting, the action in both ends of the cylinder will be the .same.

The point, 51, on the indicator diagrams or curves shown in 'Fig. 2, indicates the compression. pressure of lbs. of air in the cylinder at the commencement of the stroke of the piston. The line, 51 to 52, indicates the pressure during the time that steam is flowing from the steam chest into the cylinder. The point. 5:2. the cutting oil point. The line 52 to 53 indicates the reducing of the pressure during the expansion of the mixture of air and steam. The line to 54 and to indicates the pressure conditions during the time that the piston has uncovered the exhaust port and the air, mist and possibly some steam is flowing into the settling chamber. The line to 56 indicates the pressure during the time the valve, 10, is being held. open by the valve motion 13, la, 15, 16. The line 56 to 51 indicates the pressure during the compressing ot the air.

Now it air alone should be used, the expansion utter cutting oil would roughly approximate the pressures indicated by the line. 52 to 5'7, and it steam alone should be used the pressures during expansion would,

approximate those shown by line, 52 to 58.

Although I could use an initial pressure of 35 lbs. and expand to atmospheric pressure and the engine would work within the scope of this invention yet-l prefer to have the expansion go further than to atmos pheric pressure :tor it is obvious that the greater the volume of expansion the lowerthe temperature atthe end of the stroke oi the piston which means that more of the steam will be condensed by the expanding of the mixture oi? air and steam with a given ratio of air to steam at a commencing pressure of 35 lbs, and consequently more of the heat will be converted into work with a. smaller amount of air.

Assuming that the expansion line 52 to 58 indicates that steam has X]')?t11l(l from 35 lbs. to 20 inches of vacuum then the temperature would tall from aboutf lh) to about 162 degrees. Air in expanding through the same range of pressure would tall in term peratnre as indicated by the line, 52 to 57,

o z u LO e from 280 degrees to a temperature that is far below that of steam notwithstanding the fact that considerable heat would be transferred from the cylinder walls to the air within. For the reason that there would be considerable transferring of heat from the compressed air and steam to the cylinder walls during the first part of the stroke and later on in the stroke from cylinder walls to the air and the remaining steam it would be practically impossible to plot curves that would be accurate indications of the pressures during expansion, consequently I do not intend that the indicating curves shown in Fig. 2, be considered as being any more than rough approximations of the pressures that are obtained in the cylinder.

It much mist should be returned to the cylinder much of the heat of compression would be absorbed by this mist being rcevaporated so that loss of efficiency would result.

I use an initial steam pressure on the cylinder that approximates lbs. and 280 degrees temperature in the above description of my invent-ion although I do not confine myself to this one pressure. Pressures both higher and lower could be employed to advantage in some cases.

.A governor, t, connected to the steam valve operating motion can control the point of cut off of the steam valves. 4 and 5, so that the cutting oii' point, 52 will be nearer to or farther away from the point, 51. In other words the steam will follow the piston for a. shorter or a longer distance in its stroke depending on the power requirements. lVhen the point of cut oiii is shitted the expansion pressure must necessarily change so that the line, 52 to 53 will be below or above the position shown in the diagram. Obviously there would be more heat get into the settling chamber, 8, when the point of cut off is farther from point 51, but in order that the air" will always be brought to approximately the same temperature in the chamber, 8, I employ the cooling coil, 23, through which flows a cooling agent having the cooling capacity that will bring the air in the chamber 8, to the temperature desired.

As the temperature in the chamber, 8, can only reduce and never raise by the action of the cooling coil, 23, it is obvious that the air in this chamber, 8, cannot be at any other than maximum humidity. The slight pressure that is applied in order to compress this air and force it into the reservoir, 17, would change the relative humidity in this reservoir, but when the pressure is relieved by the air flowing into the cylinder during flushing, the pressure will lower again and the humidity will obviously return to the maximum I do not consider that my claims refer to this invention as applied only to a reciproeating engine in the working cycle herein claimed. Any kind of an engine that can be operated by the steam and air mixture working under approximately the conditions above described I consider as being covered by my claims which are:

l. A steam engine working cycle, which, commences with the displacing of the exhaust volume by the flowing of a charge of air of approximately 100 per cent humidity into an engine cylinder at the finish of a working stroke; then compressing into the clearance space between the piston and the end of the cylinder the said air to a certain pres sure and temperature; then inixin in this compressed air steam having approxin'iately the same temperature and pressure; then flowing in steam to the cutting off point of the stroke and then expanding until all or the greater part of the steam of the mix ture is condensed into a mist; then flushing the mixture of air and mist from the cylinder into a separating chamber; then separating the mist from the air in said chamber and withdrawing the collected water; then cooling the air to a desired temperature but maintaining a humidity of 100 per cent; then forcing the said air at a slight pressure into a reservoir; then with said air displacing the exhaust and charging the cylinder at the end of a subsequent working stroke of the piston.

2. A- steam engine working cycle, which, commencing at the finish of a working stroke of the piston the exhaust volume in the cylinder is displaced by the flowing oi a charge of air of approximately 100 per cent humidity into the engine cylinder then with the piston compressing into the clearance space, the said air to a certain pressure and temperature; then mixing into this compressed air, steam having approxin'iately the same temperature and pressure; then flowing in steam to the cutting off point of the stroke and expanding until all or the greater part of the steam of the mixture is condensed into a mist; then flushing themixture of air and mist from the cylinder into a separating chamber; then separating in said chamber the mist from said air; then cooling said air but maintaining the humidity at 100 per cent; then accumulating said air into a reservoir for displacing the ex haust of and charging the cylinder at the commencement of a subsequent cycle.

3. A step in a steam engine working cycle, the displacing of the exhaust volume by the flowing of air of approximately 100 per cent humidity into an engine cylinder, then with the piston, compressing into the clearance space the said air to a certain pressure and temperature, then mixing in this compressed air steam having approximately the same temperature and pressure; then flowing in steam to cutting off point of the stroke and expanding until the greater part of the steam of the mixture in the cylinder is condensed into a mist, then separating the mist from the air and returning the same air to the same cylinder for a subsequent cycle.

4:. In a steam engine Working cycle, the displacing of the exhaust volume by the flowing of a charge of air of approximately 100 per cent humidity into an engine cylinder then With the piston compressing into the clearance space the said air to a certain pressure and temperature then mixing in this compressed air steam having approximately the same temperature and pressure, then flowing in steam to the cutting ofi' point of the stroke and expanding until practically all or greater part of the steam of the mixture in the cylinder is condensed into a mist, then flushing the mixture or air and mist from the cylinderinto a separating chamber by using a displacing charge of air at approximately 100 per cent humidity, said displacing charge of air having been previously passed into and through said separating chamber and said displacing charge of air having been brought to a certain pressure Or vacuum in said separating chamber.

FRANK J. WOOD. l/Vitnesses:

CHARLES L. MoOLUsKnY, THOMAS CAsEY. 

